Metal-matrix composites, or MMCs, most commonly consist of aluminum alloys which are reinforced with particles of a hard ceramic phase, such as silicon carbide (SiC). These alloys have high elastic stiffness which is useful in applications such as brake-assemblies for automobiles. The MMCs are made by physically mixing particles of SiC into the molten metal. Several strategies for introducing the ceramic particles have been invented, but all of them use ceramic powders and the metal as the starting constituents for the fabrication of the MMCs.
Survey of prior art in this area reveals that there exist processes, which cover only production of nano-sized metal powder (US Patent Publication No. US20060167147A1) and the mixing of nano-sized powders of metal and ores in the solid state. There is no prior literature/patent on the production/fabrication of metal matrix composites involving solid-liquid interactions.
The principal limitation of these methods is the difficulty of incorporating ceramic particles of nanoscale dimensions (typically less than one thousand nanometers) into the melt. This limitation arises from the tendency of the ceramic particles of this size to agglomerate when in the powder form (nanoscale particles in a powder attract and bond to one another due to van der Waal's force, because this force increases highly nonlinearly with decreasing particle size). These agglomerates are difficult to break up into individual particles when added to the liquid metal. Without a uniform dispersion of the nanoscale particles, the benefit of creep resistance and good yield strength at elevated temperatures cannot be achieved. Aluminum and magnesium-based MMCs with a uniform nanoscale dispersion of the ceramic phase would be an enabling technology for the next generation automobile engines, jet engines, and other aerospace applications.